Gardens' Bulletin Singapore 71 (2): 445–457. 2019 445 doi: 10.26492/gbs71(2).2019-13 A new species of Hornstedtia and a new species record of Globba (Zingiberaceae) from Palawan, Philippines R.V.A. Docot1, N.P. Mendez2,3 & C.B.M. Domingo4 1 Department of Biological Sciences, Institute of Art and Sciences, Far Eastern University, Nicanor Reyes Sr. Street, Sampaloc 1015, Manila, Philippines [email protected] 2 Department of Biology, College of Arts and Sciences, Central Mindanao University, University Town, Musuan, 8710 Bukidnon, Philippines 3 Centre for Biodiversity Research and Extension in Mindanao (CEBREM), Central Mindanao University, University Town, Musuan, 8710 Bukidnon, Philippines 4 The Graduate School, University of Santo Tomas, España Boulevard, Sampaloc 1008, Manila,Philippines ABSTRACT. During recent botanical exploration in the province of Palawan, Philippines specimens were collected of a new species, Hornstedtia crispata Docot, and a new species record for the Philippines, Globba francisci Ridl., both from the ginger family Zingiberaceae. The new species is described and illustrated here along with an assessment of its conservation status. Keywords. Borneo, endangered, Globba aurea, Hornstedtia hainanensis, Hornstedtia sanhan Introduction Palawan is an archipelagic province comprising of approximately 1,780 islands and islets at about 14,897 km2, making it the largest province in the Philippines (Fernandez et al., 2002). About 48% of the province is covered with vegetation, including tropical lowland evergreen rainforest, lowland semi-deciduous (seasonal/monsoon) forest, montane forest, and forest-over-limestone (PCSDS, 2015). Within this remaining forest are unique species of terrestrial flora and fauna, including 1700−3500 angiosperms, of which 15−20% are endemic to the country (Sopsop & Buot, 2009). There is strong evidence that Borneo and Palawan were once connected by a land bridge based on bathymetric data (Woodruff, 2010) and from animal distributions (Heaney, 1986). This hypothesis is further supported by plant distributions (e.g. Poulsen & Docot, 2018 for Etlingera sessilanthera R.M.Sm.) and through biogeographical studies using molecular data to explain colonisation of the Philippines from Borneo via Palawan (e.g. Brown & Guttman, 2002 for Rana), or the other way around (e.g. Hughes et al., 2015 for Begonia L. sect. Baryandra A.DC.) Despite these efforts, further studies are still needed to support this hypothesis. 446 Gard. Bull. Singapore 71 (2) 2019 Our knowledge of the Zingiberaceae of the Philippines has been updated as a result of recent botanical explorations focused on the collection of gingers (e.g. Naive, 2017; Naive & Alejandro, 2018; Naive et al., 2018; Ambida et al., 2018; Poulsen & Docot, 2018; Acma et al., 2019; Docot et al., 2019a, b). Ridley (1905) enumerated 19 species of Philippine Zingiberaceae but now 122 species are known, of which 68% are endemic (Pelser et al., 2011 onwards; Zingiberaceae Resource Centre, 2019). Thirteen of these species occur in Palawan, five of which are endemic to the province (see Table 1 for a list of species in Palawan). Hornstedtia Retz., as currently circumscribed, comprises c. 40 species distributed from the Himalayas to Queensland with a centre of diversity in continental Southeast Asia and Malesia. Sixteen species are found in Borneo (Lamb et al., 2013; Zingiberaceae Resource Centre, 2019). The genus can be easily recognised by the involucre of tightly overlapping sterile bracts that enclose the flowers near or at the uppermost part of the corolla tube and by the flat receptacle or condensed rachis (Smith, 1985). In the Philippines, Hornstedtia is represented by six species of which five are endemic and one, Hornstedtia havilandii (K.Schum.) K.Schum., is also found in Borneo (Pelser et al., 2011 onwards). Globba L. species are distributed from Sri Lanka to Australia with a centre of distribution in monsoonal continental Southeast Asia (Williams et al., 2004). Members of this genus are easily distinguished by their small, delicate flowers with small labellum and elongated, arched stamen (Smith, 1988; Leong-Škorničková & Newman, 2015). A total of eight species of Globba are currently known in the Philippines, all of which are endemic except Globba marantina L., a species which is naturalised in tropical regions around the world (Pelser et al., 2011 onwards). Botanical fieldwork focused on collecting gingers conducted by the authors in Palawan in 2017−2018 led to the collection of unidentified Globba and Hornstedtia species. After careful morphological comparison with known Philippine species and those occurring on neighbouring islands (e.g. Borneo and Sulawesi), the authors concluded that the Hornstedtia species is new to science, and the Globba species is Globba francisci Ridl., a species hitherto endemic to Borneo (Lamb et al., 2013). The new species is described and illustrated here along with an assessment of its conservation status. It is likely that there are still numerous species awaiting discovery in Palawan and many species already known from Borneo will eventually be discovered in Palawan or vice versa. Materials and methods Herbarium collections, including high-resolution images of specimens, from BISH, BM, BO, E, F, FEUH, G, GH, K, L, MO, NY, P, PNH, S, SING, U, US, USTH and Z, along with published morphological descriptions of most similar species (e.g. Smith, 1988; Newman, 1995; Ye et al., 2018), especially those from the Philippines and neighbouring islands, were examined and compared to our recently collected specimens. Specimens seen only as a digital image available online are denoted New ginger species and records from Palawan 447 Table 1. The 15 Zingiberaceae species currently known in Palawan including their distribution status in the Philippines and publication record for Palawan. An asterisk (*) indicates that the species is endemic in Palawan. Species Distribution First recorded in Palawan Alpinia foxworthyi Ridl. * Endemic Ridley (1909) Alpinia galanga (L.) Willd. Widespread and Merrill (1923) cultivated Alpinia haenkei C.Presl Endemic Ridley (1909) Alpinia illustris Ridl. * Endemic Ridley (1909) Curcuma zedoaria (Christm.) Roscoe Widespread and Merrill (1923) cultivated Etlingera philippinensis (Ridl.) R.M.Sm. Endemic Ridley (1909) Etlingera sessilanthera R.M.Sm. Native Poulsen & Docot (2018) Geocharis fusiformis (Ridl.) R.M.Sm. var. Endemic Pelser et al. (2011 fusiformis onwards) Globba aurea Elmer * Endemic Elmer (1915) Globba francisci Ridl. Native here Globba marantina L. Widespread and Merrill (1923) cultivated Globba ustulata Gagnep. * Endemic Gagnepain (1901) Hornstedtia crispata Docot Endemic here Wurfbainia hedyosma (I.M.Turner) Endemic Merrill (1923) Škorničk. & A.D.Poulsen Wurfbainia palawanensis (Elmer) Endemic Elmer (1915) Škorničk. & A.D.Poulsen * with an asterisk (*). The herbarium acronyms follow Thiers (continuously updated). The species description of the new species follows the style of recently published species of Hornstedtia (e.g., Leong-Škorničková et al., 2016; Ye et al., 2018) and the terminology in Beentje (2012). The extent of occurrence (EOO) and area of occupancy (AOO) of the new species were calculated using the Geospatial Conservation Assessment Tool (GeoCAT) (Bachman et al., 2011: www.geocat.kew.org). These data were then compiled to assess its conservation status using the International Union for Conservation of Nature criteria (IUCN, 2016). Furthermore, the coordinates of the localities based on information 448 Gard. Bull. Singapore 71 (2) 2019 on herbarium labels were collected and generated in QGIS v. 2.18 (Quantum GIS Development Team, 2016), creating a distribution map (Fig. 4). Taxonomy Hornstedtia crispata Docot, sp. nov. Similar to Hornstedtia sanhan M.F.Newman but differs in the petiolate lamina (vs sessile); significantly wider lamina (10−16 vs 5−7 cm); oblong labellum (vs spathulate); presence of a 3−4 mm long petaloid and crispate anther crest; and subglobose epigynous glands (vs subulate). − TYPE: Philippines, Luzon, Palawan, Brooke’s Point, Barangay Malis, Mount Mantalingajan, 8°45'20.7"N 117°39'25.0"E, 1228 m, 28 September 2018, R.V.A. Docot et al. 0191 (holotype PNH [accession no. 256990]; isotypes FEUH incl. spirit, L, USTH). (Fig. 1 & 2). Terrestrial herb in loose clumps. Rhizome 1.5−3 cm in diameter, yellowish-brown, scales thick, brown. Leafy shoot 4−8 m tall, arching to various degrees, base swollen, 5−6 cm wide; sheath reticulated, reddish-green when young, becoming light green when mature, glabrous; ligule ovate, 15−20 × 10−15 mm, reddish when young, becoming mid green when mature, the centre sericeous, becoming glabrous towards the margin, apex rounded; petiole 15−25 mm long, reddish when young, becoming light green when mature; lamina oblong, 55−70 × 10−16 cm, mid to dark green above, paler beneath, glabrous on both sides, base rounded, apex acute, margin reddish, slightly undulate, ciliate. Inflorescence 7−13 × 4−6 cm, emerging from the ground, receptacle flat, with many flowers, one open at a time; peduncle erect, 2−3 cm long, covered with thick and brown peduncular bracts; sterile bract ovate, largest 40−60 × 30−45 mm, becoming narrower towards the centre of the inflorescence, lower half sericeous, the hairs white, upper half bright red, glabrous and coriaceous, margin entire, apex rounded and emarginate; fertile bract oblong, 40−55 × 15−25 mm, split to the base, translucent white, apex acute; bracteole oblong, 20−30 × 7−12 mm, split to the base, translucent